Late-Holocene salinity changes in Lake Ogawara, Pacific coast of northeast Japan, related to sea-level fall inferred from sedimentary geochemical signatures

Nara, Fumiko*; Watanabe, Takahiro; Matsunaka, Tetsuya*; Yamasaki, Shinichi*; Tsuchiya, Noriyoshi*; Seto, Koji*; Yamada, Kazuyoshi*; Yasuda, Yoshinori*

Palaeogeography, Palaeoclimatology, Palaeoecology, 592, p.110907_1 - 110907_11, 2022/04

https://doi.org/10.1016/j.palaeo.2022.110907

Radiocarbon dating, tephrochronology, and geochemical signatures such as bromine (Br), iodine (I), total sulfur (TS), total organic carbon (TOC), and total nitrogen (TN) in a continuous sediment core (OG12-2) were applied to estimate past salinity change on the Lake Ogawara, Pacific coast of northeast Japan. Since the Lake Ogawara was the inner bay of the Pacific Ocean and became the brackish lake in the late Holocene, clarifying the past salinity change on the lake Ogawara could give us important insight into the past sea level changes of the Pacific Ocean. The core OG12-2 has two tephra layers, the Towada eruption and the Changbaishan eruption (B-Tm: AD 946). The age model for the core OG12-2 was established using the radiocarbon measurements of the plant residues in the core, also was constrained by the B-Tm tephra. Depletions of marine-derived elements (Br, I, and TS), from 88.4 to 64.2 mg/kg, 20.0 to 14.1 mg/kg, and 3.1 to 1.1 mass %, respectively, were observed in the layers with 2200-2000 cal BP. These results indicate paleosalinity changes from saline (inner bay) to brackish conditions within Lake Ogawara caused by sea level fluctuations during the late Holocene.

Dynamics of water in a catalyst layer of a fuel cell by quasielastic neutron scattering

Ito, Kanae; Yamada, Takeshi*; Shinohara, Akihiro*; Takata, Shinichi; Kawakita, Yukinobu

Journal of Physical Chemistry C, 125(39), p.21645 - 21652, 2021/10

https://doi.org/10.1021/acs.jpcc.1c06014

Structural investigation of sulfonated polyphenylene ionomers for the design of better performing proton-conductive membranes

Shiino, Keisuke*; Otomo, Toshiya; Yamada, Takeshi*; Arima, Hiroshi*; Hiroi, Kosuke; Takata, Shinichi; Miyake, Jumpei*; Miyatake, Kenji*

ACS Applied Polymer Materials (Internet), 2(12), p.5558 - 5565, 2020/11

https://doi.org/10.1021/acsapm.0c00895

Design of HTTR-GT/H test plant

Yan, X.; Sato, Hiroyuki; Sumita, Junya; Nomoto, Yasunobu*; Horii, Shoichi*; Imai, Yoshiyuki; Kasahara, Seiji; Suzuki, Koichi*; Iwatsuki, Jin; Terada, Atsuhiko; et al.

Nuclear Engineering and Design, 329, p.223 - 233, 2018/04

https://doi.org/10.1016/j.nucengdes.2017.10.009

The pre-licensing design of an HTGR cogeneration test plant to be coupled to JAEA's existing test reactor HTTR is presented. The plant is designed to demonstrate the system of JAEA commercial plant design GTHTR300C. With construction planned to be completed around 2025, the test plant is expected to be the first-of-a-kind nuclear system operating on two of the advanced energy conversion systems attractive for the HTGR closed cycle helium gas turbine for power generation and thermochemical iodine-sulfur water-splitting process for hydrogen production.

HTTR-GT/H test plant; System design

Yan, X.; Sato, Hiroyuki; Sumita, Junya; Nomoto, Yasunobu; Horii, Shoichi; Imai, Yoshiyuki; Kasahara, Seiji; Suzuki, Koichi*; Iwatsuki, Jin; Terada, Atsuhiko; et al.

Proceedings of 8th International Topical Meeting on High Temperature Reactor Technology (HTR 2016) (CD-ROM), p.827 - 836, 2016/11

Pre-licensing basic design for a cogenerating HTGR test plant system is presented. The plant to be coupled to existing 30 MWt 950C test reactor HTTR is intended as a system technology demonstrator for GTHTR300C plant design. More specifically the test plant of HTTR-GT/H aims to (1)demonstrate the licensability of the GTHTR300C for electricity production by gas turbine and hydrogen cogeneration by thermochemical process and (2) confirm the operation control and safety of such cogeneration system. With construction and operation completion by 2025, the test plant is expected to be the first of a kind HTGR-powered cogeneration plant operating on the two advanced energy conversion systems of closed cycle helium gas turbine for power generation and thermochemical iodine-sulfur water-splitting process for hydrogen production.

Design study on safety protection system of JSFR

Ishikawa, Nobuyuki; Chikazawa, Yoshitaka; Fujita, Kaoru; Yamada, Yumi*; Okazaki, Hitoshi*; Suzuki, Shinichi*

Proceedings of 2012 International Congress on Advances in Nuclear Power Plants (ICAPP '12) (CD-ROM), p.483 - 489, 2012/06

The development of safety protection system for JSFR is progressed in terms of logic circuits, selection of trip signals and its setting values for reactor trip. In addition, it is necessitated to evaluate the satisfaction for requirements of the safety protection system by safety analyses considering comprehensive parameter ranges. For this purpose, we will report the current status of the development focusing on the evaluation results for satisfaction of safety protection system based on safety standard.

Crossover from coherent quasiparticles to incoherent hole carriers in underdoped cuprates

Hashimoto, Makoto*; Yoshida, Teppei*; Tanaka, Kiyohisa*; Fujimori, Atsushi*; Okusawa, Makoto*; Wakimoto, Shuichi; Yamada, Kazuyoshi*; Kakeshita, Teruhisa*; Eisaki, Hiroshi*; Uchida, Shinichi*

Physical Review B, 79(14), p.140502_1 - 140502_4, 2009/04

https://doi.org/10.1103/PhysRevB.79.140502

Distinct doping dependences of the pseudogap and superconducting gap of LaSrCuO cuprate superconductors

Hashimoto, Makoto*; Yoshida, Teppei*; Tanaka, Kiyohisa*; Fujimori, Atsushi*; Okusawa, Makoto*; Wakimoto, Shuichi; Yamada, Kazuyoshi*; Kakeshita, Teruhisa*; Eisaki, Hiroshi*; Uchida, Shinichi*

Physical Review B, 75(14), p.140503_1 - 140503_4, 2007/04

https://doi.org/10.1103/PhysRevB.75.140503

We have performed a temperature-dependent angle-integrated photoemission study of LaSrCuO covering from lightly doped to heavily overdoped regions and oxygen -doped LaCuO. The superconducting gap energy was found to remain small for decreasing hole concentration while the pseudogap energy and temperature increase. The different behaviors of the superconducting gap and the pseudogap can be explained if the superconducting gap opens only on the Fermi arc around the nodal (0,0)- direction while the pseudogap opens around . The results suggest that the pseudogap and the superconducting gap have different microscopic origins.

Development of environment stress tolerant population in netted melon "Earl's Favorite" by ion beam breeding

Maejima, Shinichiro*; Katai, Hideyuki*; Taneishi, Motohiro*; Yamada, Hidenari*; Ohashi, Hirokazu*; Hase, Yoshihiro; Tanaka, Atsushi

no journal, , 

no abstracts in English

Current status and perspective of neutron polarizing device development and application in neutron scattering experiments in Japan

Oku, Takayuki; Kira, Hiroshi; Sakaguchi, Yoshifumi; Sakai, Kenji; Suzuki, Junichi; Nakamura, Mitsutaka; Shinohara, Takenao; Koizumi, Satoshi; Takata, Shinichi; Aizawa, Kazuya; et al.

no journal, , 

Material and Life science experimental facility (MLF) of J-PARC center have started user program in which experiments using pulsed neutron beam are available from December 2008. The source power of the pulsed spallation neutron source JSNS is gradually increasing and now reached 120 KW, where its final goal is 1 MW. With increasing the neutron source power, the number of user programs is also increasing. In this situation, a 5-years project, which aims at higher efficient utilization of neutrons in neutron scattering research, have started since 2008 in Japan. Six Japanese institutes join this project, and neutron optical devices including He spin filters, neutron imaging device and neutron scattering method are being developed. In this paper, we report the current status of optical devices development and application and future perspective in Japan.